An olympic sprinter readies for a race. after the sound of the starting gun, he propels himself forward from the starting block
and immediately grimaces in pain, grabbing for the back of his thigh. within 48 hours he begins noticing extensive bruising on the back of his thigh extending into the back of the knee. he now has difficulty rising from a seated position and flexing his knee. bending at the waist generates more pain. which muscle is likely injured?